Microphones intrinsically can detect a specific range of audio signal frequencies. Although many audio signals of interest typically are within that range, many undesirable audio noise signals typically are at that lower end of the range. For example, wind noise commonly has frequencies below 200 Hertz. To substantially eliminate this noise, a microphone simply may be configured to have a low frequency cutoff point (also known in the art as the “minus 3 DB point”) of about 200 Hertz. A microphone configured in this manner therefore should not appreciably sense audio signals below about 200 Hertz.
One problem with this approach, however, is that some audio signals of interest also have frequencies below 200 Hertz. Accordingly, such “noise reducing” microphones cannot detect desirable low frequency audio signals. To avoid this problem, those in the art extend the low frequency cutoff to a much lower value, such as 40 Hertz.
This dilemma represents an ongoing tradeoff. Either a microphone can detect low frequency signals, and thus undesirably detect noise, or it does not detect noise but cannot detect desirable low frequency signals.